#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<iostream>
using namespace std;
int main()
{
	int sum = 0;
	int a = 0, b = 0, c = 0;
	scanf("%d %d %d", &a, &b, &c);
	if (a >= 0 && a <= 100 && b >= 0 && b <= 100 && c >= 0 && c <= 100)
	{
		sum = 0.2 * a + 0.3 * b + 0.5 * c;
		cout << sum << endl;
	}
	return 0;
}